Conventionally, in the process for polishing a product wafer, after attaching a pad, a polishing head, and a grid (dresser), the QC of the polishing equipment is performed to monitor the various status quantities such as a removal rate and uniformity thereof, and then, it is determined whether or not the polishing equipment can be used in the fabrication process. When starting the process of the product wafer, the film thickness prior to the polishing is measured. Alternatively, assuming that the film thickness prior to the polishing is set in a control limit, the polishing condition is determined so that the film thickness after CMP satisfies the control limit, and the parameters of the recipe is determined for each type of the product wafer and process (set for each layer of the films to be polished). Then, the process is started.
After a plurality of product wafers are processed, the state of the polishing equipment which has been used in the process is changed with the passage of time due to the load at the time of polishing, and the removal rate in the wafer surface becomes different from that at the time of the QC of the equipment. As a result, there arises a problem that the film thickness after CMP does not satisfy the control limit in the recipe determined based on the removal rate monitored in the QC of the equipment.
Furthermore, the film thickness before the polishing of the product wafer or the surface profile of the wafer depends on the state of various types of equipment, a device shape/pattern, and a wiring shape/pattern in the process flow through which the wafer has been processed. Therefore, due to the difference in thickness and surface profile of the various types of product wafers before the polishing, it is necessary to determine the polishing condition in accordance with the types of the films and structures in order to set the film thickness after CMP to a predetermined thickness.
As a consequence, the run-to-run method has been devised, in which the recipe is adjusted by estimating the removal rate based on the thickness before/after CMP of the product wafer which has been already processed and the polishing conditions and estimating the wafer condition determined by the process flow.
For example, Japanese Patent Application Laid-Open No. 2002-124497 discloses the method in which the film thickness before/after CMP of the product wafer and the polishing conditions are compared with the film thickness before/after CMP of the wafer serving as a reference and the polishing conditions so that the polishing time and the polishing pressure are fed back to the subsequent process.
Furthermore, the removal rate is changed in a different manner at respective portions of the distribution within the range of the wafer surface, and an influence on the change in the film thickness after CMP due to the difference in the film thickness before CMP and in the surface profile resulting from the process flow before polishing the product wafer also differs at respective portions of the surface. As a consequence, the polishing conditions determined by the within-wafer distribution of the removal rate obtained in the QC of the equipment and the polishing conditions determined by the within-wafer distribution of the film thickness before CMP and the surface profile set for the product and process cannot assure that the film thickness after CMP at each portions in the wafer surface satisfies the control limit.
Therefore, a method for improving the removal rate of the polishing equipment and the uniformity in the wafer surface of the equipment performance of other equipment in the various processes has been suggested. Furthermore, a method for adjusting the within-wafer distribution of the processing capability in the latter process in order to cancel the within-wafer distribution of the status quantity of the processed product wafer generated in a certain process has been suggested.
For example, the wafer polishing equipment and the method for fabricating a semiconductor device using the wafer polishing equipment described in Japanese Patent Application Laid-Open No. 9-323261 has suggested the method for the CMP in which the discharge amount of the polishing agent (slurry) to a polishing cloth (pad) is adjusted so as to make the wafer state after CMP uniform.
Also, the polishing equipment described in Japanese Patent Application Laid-Open No. 11-19864 has described the method for the CMP in which the within-wafer distribution of the removal rate (processing capability) is adjusted at the time of the polishing based on the distribution of the film thickness of the wafer before CMP, thereby making the film thickness after CMP uniform.
The processing method, the measurement method, and the method for fabricating a semiconductor device which are described in Japanese Patent Application Laid-Open No. 2002-184733 have described the method in which a correlation function of a status quantity at each within-wafer portion is obtained based on the distribution data in the wafer surface between a plurality of wafers or between a plurality of processes of the same wafer, and the process conditions for minimizing the uniformity in the wafer surface are obtained by using the correlation function.
The dry etching equipment of an aluminum film and an aluminum alloy film, the dry etching method, the apparatus for fabricating a semiconductor device, the method for fabricating a semiconductor device and the semiconductor device described in Japanese Patent Application Laid-Open No. 11-61454 have described the method for the dry etching for etching an aluminum film, in which a gas flow rate at the etching time is adjusted, thereby improving the uniformity of an etching rate in the wafer surface.
The method for determining a control condition of the thermal treatment equipment, thermal treatment equipment, and a thermal treatment method described in Japanese Patent Application Laid-Open No. 2002-43300 have described the method for eliminating the nonuniformity in the thickness of an oxide film in the wafer surface generated by the thermal treatment process, in which a rate of the film formation amount with respect to a temperature is obtained as the within-wafer distribution based on the within-wafer distribution of the film thickness, and the temperature distribution in the wafer surface is determined so as to make the film thickness uniform.